Apparatus for gasifying liquid



Jan. 9, 1951 A. G. HOWARD 2,537,761 APPARATUS Foa GASIFYING LIQUID Filed June 5, 1946 l Patented Jan. 9, 1951 UNITED STATES PATENT ortica 12 Claims.

f The invention relates to improvements in the method of and apparatus for gasifying a liquid, and is concerned particularly with an improved apparatus for producing and distributing an insecticidal gas for use to Ycontrol insects such as are common to the milling industry and the like.

The kmethod and apparatus involving the prinpples of the present invention constitute improvements over the method and apparatus shown and claimed in my copending application Serial No. 580,447, filed March l, 1945.

In the instant apparatus means is provided to maintain a plentiful supply of liquid insecticide within the apparatus at all times for processing and ultimate distribution in gaseous form through a system with which the apparatus is associated. The apparatus is particularly useful to gasify insecticide originally in liquid form, and it is associated with a system of distribution that facilitates the discharge of the insecticidal gas under pressure directly into bins, processing machines and other 'containers or equipment used in the food processing industry, such as, for example, in the milling or baking industries.

Treatment'of flour and flour milling or dough handling equipment with an insecticide is required at regular intervals to control insects which are particularly prevalent in such equipment. More specifically, treatment of flour and flour or dough handling equipment with known liquid insecticides by means of an atomizing sprayer is not entirely satisfactory because of the attendent objectionable features which usually result from .the application of a fumigant in its liquid state. It is, therefore, an object of the present invention to provide a novel apparatus especially adapted to pre-vaporize a liquid insecticide, in a gaseous form as distinguished from mere atomization and to discharge such insecticidal gas under pressure directly into the interior of the bin, processing machine or other container or equipment so as to cause the insecticidal gas to blanket and commingle with the contents thereof.

Such treatment of the contents in storage bins or of processing equipment preferably is performed at regular intervals and for predetermined peiods of time. It is, therefore, another object ofthe present invention to provide' a time controlled apparatus embodying novel structural features adapted to generate and distribute a predetermined quantity of insecticidal gasat selected time intervals.

Another object is to provide an insecticidal gas generatingr apparatus with novel means to insure delivery of a plentiful supply of liquid in.. secticide to the apparatus at all times.

Another object of the present invention is to provide an apparatus .of the kind referred to which is highly efficient in use, not expensive to manufacture, install or maintain, and which is entirely automatic in starting, operating and shut-down.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by Way of illustration, shows a preferred embodiment and the principle thereof. Other embodiments of the invention embodying the same principle may be 'used and structural changes may be made as desired by those skilled in the art without departing from the present invention and purview of the appended claims.

In the drawing:

Fig. 1 illustrates an embodiment of the apparatus vused for carrying out themethod of the present invention, showing the casing enclosing such apparatus broken away.

Fig. 2 is an elevational View showing a distributing conduit and dispensing valve in association with a wall of a kbin or other piece of our handling equipment.

The embodiment of the apparatus disclosed in the accompanying drawing and useful in carrying out the present method of gasifying an in A pipe I6, connected at one end to the head of the air compressor I3, is connected at its other end into a separator H which functions to remove mosture from air passing therethrough. Water collected in the separator may be withdrawn through a drain I8@ Substantially dry air leaving the separator l1 under pressure flows through a pipe line I9 into the air pressure tankv l2 and a check vvalve 2l isprovided in said pipe line to prevent a reverse now.

rlhe air pressure tank l2 may be of a size suitable to be enclosed within the housing Il and it preferably is constructed to withstand anv internal working pressure of between 6 to 15 p. s. i. and is provided adjacent its upper end with a safety blow-off valve 22 set to operateat l5 p. s. i. so as to avoid the possibility of the pressure within the tank reaching dangerous proportions. The air pressure tank has suiilcient capacity to permit precipitation and condensation of moisture contained in the air entering it through the pipe line I9 and a drain 20 is provided at the bottom thereof through which such condensate may be removed.

An outlet linei23lleads from the tank I2.and.iti

includes a silica-gel dehydrator 23' that is effective to remove any moistureremaining in the air. passing from said tank. The line 23 is connectedY With the air pressure tank adjacentlits-.upperend and it also includes a T 24 and a check valve 25 located closely adjacent to the secon'd"T"'2611 provided on the end of said linefor:purposesfto.A

be explained hereinafter. The T 26 has connected into one of its outlets a conduit 21`of 'a" diameter considerably smaller than the diameter ofthe pipeline 23. This conduit 21is'connected into the upper portion of a liquid pressure tank 281;- as at 29, so thatwhen a-'predetermined pressurel -is created Within the air pressure tank I2 alike pressurezis maintained Within the head of the liquid pressure tank 28.

The'liquid pressure tank .28is adapted to containtherinsecticidal liquid that is to be converted into an'- insecticidal gas and it isA one of the purposesoflthe present invention to afford means whereby said liquid pressure tanki23 always con'- tainsla substantial Volumetof said-.liquid upon startinggasifying operation. Accordingly, a container, such as thebarrel, tank or the like, inwhich the inseoticidal liquid is originally contained-"upon delivery, may be suitably located, as shown, outside of the apparatus housing and at a' level below the level of the highest point in the liquidsystem of thek apparatus.k This 'container 3ilis then'connected through an `.inlet 'pipe line 31; including-a shut-oil valve 32., balileSl, check valves 33 and a T 34, with an inlet 35 at 'thelower portion of the? liquid pressure tank 28. The baille 3l is provided for aY purpose to b'e'describ'ed hereinafter. When-'the shut-ofi valve 32-isopen and the level of the liquid-in the container 30 is higher than the' level of the liquid Within the liquid vpressure tank 28, and vWhile/thet apparatus isnot in operation, liquid will ilowfrom the containerillto the liquid pressure tank until such timeias the levelsiof thetwobodies of liquid are equal, crunless such leveling oi isprevented by the building-'up of' an air pressure head" within the upperportion .of the liquidpressure tank 28'.

Such'pressure'headis, ofcourse, always main-v tained duringlcompressor operation because the upperportion of the pressure tank is in direct the compressor' is' not operating andthat the presure'in'the air pressure tank I2`hasffallen" belov.7 given pressure. If the head of` liquid within vthe container 'is of vsuiiicient weight` toovercome Vthe pressure head and the Weight' ofI auf liquid'. then.` in the liquid pressure-tank" 28,? liquid willflcw into'the liquidpressuretank 23 until the pressureswithin the container 3U and 'liquid `pressureftank 281 areA equalized;

Whentheicompressor'is placed in operation to build .up-- theair pressure'intheair pressuretank |2j` the resultin'gincreased pressure head in the: liquid pressure tank-Zliwlltend toY force the liquid therein-containedoutwardly: inra direction reverse L regulation ofliquid iicvf.

to that in Which it flowed through the pipe 3l when entering the tank 28. Such reverse movement of the liquid does not result in a return of said liquid to the container 3!) because the increase in pressure Within the liquid pressure tank 28 has closed the check-valves 33. As a result, the reverse flow of liquid entering the pipe 3l at, the. liquid pressure tank. inlet 35 Will flow through the conduit 35 whichxisconnected at one end into the pipe line 3l as by means of a T 34. The other end of the conduit 3E is connected with and opens into a metering valve 31 which is preferably arestricted iiow needle type Valve provided..with.a. sight glass so as to permit visual A type of valve I have found-desirableior. use is manufactured by the Brooks .Rotameter Co. of Lansdale, Pennsylvania. Obviously,` a fresh supply, of liquid cannot be delivered to the liquid pressure tank 28 during machine-operation and as a consequence there never is any `possibility of' delivering a quantity of insecticidal -gas in excess of the liquid contents of the liquid pressure tank at the start of any period oi operation.

Theliquid entering the metering valve 31 in the form cfa sprayis adapted to be entrained in a stream of airfor Vaporization and to` thisend the metering valve is suitably connected with a plurality of air'inlet lines in a Amanner to-be described hereinafter.

One ofthe lines provided forv delivering' air to the metering valve 31 includes a conduit 38 of relatively small internal diameter, Which is connected at one` end-to the one outlet of the end T'2='and at its other end through an orifice valve 39 r`with one inlet of the YT il having direct connection, as bymeanszof a nipple 42, with the.

metering valve 31. Thus, a very small quantity of airf flowing -to the end T 26 from the pressure tank l2` is diverted through the conduit 38 forv delivery to the metering valve 31. Because air is being delivered through the pipe line 23 at all times when pressure is maintained within the air pressure tank I2, a steady flow of air under pressure is maintained within lthe conduit 38 for discharge into the metering valve 31. This stream oi'which is at'about 15 p. s. i. is, however, insulicient involume to vaporize the liquid to the degree necessary for its efficient use; consequently, a second air inlet line is provided by means of which a substantially greater volume of air but at a reduced pressure is delivered into the metering Valve;v

It'might be noted at this time that the valve 33 has a small Vent orifice therein. This is pro'- vided yto avoid the creation of an air'block in the liquid tank 28 which would prevent liquid from the supply tank 313 being delivered to tank ZSYduring the periods of non-operation of the apparatus. Also, when the apparatus is shut down, pressure in the tank 28 is relieved so that the now of liquid therefrom is arrested.

This secondary or rather the main line for delivering air under reduced pressure to the metering valve 31 includes piping 43 which is connected into and communicates'with the T 24 in the main air'distributing line 23 and it includes-a checkvalve 44 to prevent a reverse flow of air through said pipe line. nected into one side of a T45 carried in a header pipe assembly 45, which assembly includes a high pressure gauge d1, a ilow regulator valve 48, a low pressure gauge 43', a check-valve 5l and a conduit 520i reduced diameter which connects said header assembly dwith' a shut-oli valve 53 connected by a nipple 54 with one inlet of the T 4l oppositely disposed to the inlet of said T receiving the ttings 39 connecting the conduit 38 therewith. The purpose of the pipe line 43 and header assembly 46 is to insure an adequate volume of air for delivery into the metering valve 31 at a pressure considerably lower than the pressure of the air delivered to it through the conduit 38 so as to thereby create a turbulence in the air owing through said metering valve and thereby increase the absorption of liquid spray iiowing therethrough The Valve 48 serves to reduce the air pressure in line 43 from 15 p. s. i. to about 8 p. s. i. so that air enters valve 31 through line 52 at about 8 p. s. i. Liquid from the tank 28, however, is delivered to the valve 31 at the full pressure of p. s. i. f

Vapor leaving the meteringv valve 31 is delivered through a conduit 55 into one end of a gasifying or vaporizing chamber 5G for discharge through piping 51 and 58 to a feeder line 59 for distribution throughout various sections of a building within which the apparatus is located and which contains the machinery cr other equipment to be treated. The feeder line 59 may be provided with any number of distribution lines or branches commensurate with the capacity of the apparatus, and these branches, as well as the feeder line 59 may be tapped at selected intervals to receive conduits for conducting the insecticidal gas iiowing through the feeder line 59 to individual pieces of the apparatus or equipment.

The temperature of vapor owing into the chamber 56 is too low for complete gasification because of the refrigerating effect of vaporization. Complete gasification of such refrigerated vapor and the elimination of all condensation of moisture from the outside air surrounding the chamber; with objectionable dripping of such condensate on other parts of the apparatus is assured by providing means in association with the chamber for raising the temperature of said vapor which increases the moisture absorption quality of the air therein contained. To this end, a cartridge type heater element 63 is arranged within the chamber 55 and is suitably connected, as by an electrical conduit 64, with a source of current through a thermo-switch 65. The heating manifold is also provided with a pressure tube 5l suitably connected by a hydraulic line 64 with the thermo-switch 65, which switch is eiective to make and break the electrical circuit to the heating element 63.

An automatic time-control switch 66 is connected in the electrical circuit for the motor I4 so as to afford means to start and stop the apparatus and energize the heater 63 at predetermined periods of time. This` time-control switch may be of any conventional construction suitable for installation in the present apparatus. Of course, when the temperature of the manifold 56 reaches the degree required for efiicient vaporisation, during apparatus operation the thermostat switch 65 actuates to cut oi the current supply thereto.

The means, best illustrated in Fig. 2, for conducting the insecticidal gas from the feeder line 59 into the various units, may consist of a conduit 61 having a dispensing Valve 63 at its discharge end which extends through an opening in the wall of the bin or apparatus to be fumigated so that the insecticide gas flowing through the conduit 61 is delivered directly into the interior of the bin or other equipment to thoroughly blanket the entire contents thereof and comingle therewith.

Because of the possibility that the flow regulator valve 48 may on occassion stick or otherwise i6 is provided in the by-pass conduit 1Iy and is f adapted to reduce the pressure of the air in the by-pass line to about 8 p. s. i. so that vone half of the air volume delivered to the metering valve 31 through conduit 52 flows through conduit 1l while the remaining portion passes through the flow regulating valve 48. Accordingly, should the flow regulating valve become stuck while closed, at least a sufcient quantity oi air will continue to now to the metering valve 31 to avoid complete operating failure. A bleed line 13 leads from the piping 51 to the upper portion of the liquid pressure tank 28 and this line is provided with a check-valve 14 so as to prevent the movement of air from the liquid pressure tank through said line and directly into the feeder line 59 while at the same time it permits any condensate in the distribution system to return to the liquid supply when the apparatus is shut down. i Such return of condensate is possible because of the Ybleed orice Lil) in the fitting 39 and further because the now of liquid into the liquid pressure tank 28 is restrainedY by the restriction baiiie 3|' in the supply line 3l.

It should be quite evident at this time that a very elioient apparatus is provided wherein the quantity of liquid insecticide within the liquid pressure tank 28 is always maintained, at the beginning of operation, at a level necessary for eiiicient operation of the apparatus, and that when the apparatus is shut down for a period of time sulcient to allow the pressure head in the tank 23 to reach a predetermined lo-w, a fresh supply of liquid will flow into the liquid pressure tank 23 from the supply container 30. The apparatusfurther is characterized by the unique arrangement of the various controls and lines which insure the free unobstructed flow cf air and liquid to the metering valve in quantities particularly suitable to eiect the desired ydegree of vaporization of such liquid as is entrained by the air and carried into the heating manifold wherein its temperature is raised a sufiicient degree to eiect compiete and thorough gasification of the insecticide, as distinguished from mere vaporization or atomization, which insecticidal gas is delvered automatcally to the various bins or other equipment to be treated Without requiringh any attention, inasmuch as the apparatus is entirely .automatic in its operation.

It should be evident that the principle of the invention may be embodied in an apparatus embodying details varying from the details disclosed in the accompanying drawing and specifically described herein; and that, the invention may embody other modifications in the construction of the apparatus shown without departing from the spirit of the present invention or the scope of the appended claims.

I claim:

l. An apparatus for gasifying liquid compris'- ing, in combination, a liquid supply source, Ia sealed tank for liquid having an inlet at its lower end, a pipe connecting'said source with connected therewith and communicating.

asaidfinlet rvrhereby liquidf;may.'.'1low z by gravity V:connected to said line eiiective to convert liquid :flowing therethrough to a gaseous state prior to itsdischarge from the apparatus.

2. -,en apparatus intended for intermittent foperationand actuable to produce an insecticidal .gas comprising, in combination, a tank, means `effective tomaintain a supply of liquid insecticide .insaid tank, means including a compressor oper- .abletoV maintain the liquid in said tank under a .predetermined pressure, a .metering valve, means to'deliver a .spray of said liquid to said metering valve,:said metering valve having an inlet for air delivered thereto under pressure, means for idelivering air from said compressor to said inlet, la chamber through which commingled air and liquid spray is owed for discharge as an insecticidal gas, and a heating element in said chamber.

3. An apparatus intended for intermittent operation and actuable .to produce an insecticidal 'gas comprising, in combination, a tank, means effective Ito. maintain a supply or" liquid insecticide in said tank, means including a compressor operable to maintain the .liquid in said tank under la predetermined pressure, a metering valve, means to deliver a spray of said liquid to said metering valve, said metering valve having an inletV for air delivered thereto under pressure, (means for delivering air from said compressor to said inlet, a chamber through which commingled airand liquid spray is Vflowed for discharge as an 'insecticidal gas, a heating element in said chamber, and means to control operation of said heating element.

4.. An apparatus intended for intermittent operation and actuable to produce an insecticidal gas comprising, in combination, a tank, means eieotive to maintain a supply of liquid insecti- -cide in said tank, means to deliver air under pres- .sure to said tank to maintain the liquid therein under a predetermined pressure, a metering rvalve, means to deliver a spray of said liquid to said vmetering valve, said metering valve having an inlet for air delivered theretounder pressure, -means for delivering air tosaid inlet, a heater manifold through which commingled air and :liquid spray is -iiovved for discharge as an insecticidal gas, and time control means operative to control periodic operation of said apparatus.

y5. An apparatus intended for intermittent operation and actuable to produce an insecticidal gas comprising, in combination, a tank, means effective to maintain a supply of liquid insecti- .Ycide .in .said tank, means including a compressor .operable to maintain the liquid in said tank under -a Vpredetermined pressure, a metering valve,

means to deliver .a sprayof said liquid to said metering valve, said metering valve having an inlet for air delivered thereto under pressure, means for delivering air from said compressor to said inlet, a heater chamber through which comvmingled air and liquid is flowed for discharge as .aninsecticidalgaa time control means operative -vtoncnntrol periodic operation'of saidv apparatus, andY aIfloW-regulator rvalve to maintain a uniform 'air pressure.

v"6. Anzapparatus for gasifying liquid, in comrbina'tion, asealedtank for a liquid, a source of liquid supply connected to'saidztank in such man- VvnerA .that liquid. flows by gravity `into said tank, 'means` `for deliveringzair under pressure into lthe container .topmaintain the liquid therein under a pressure Agreater than the pressure ilovving liquid `into the itank lto thereby stop such flow, a meter- -ing valve to which liquid is delivered under pressurefrom said tank, an air line connecting With the metering valve through which air is delivered under pressure .pto the valve to commingle With the liquid delivered thereto, a dow regulator in said lastnamed air line, and a heater chamber Aintoyvhich -said commingled air and liquid is 'delivered Vfor discharge therefrom in the form of a gas.

'7. .-An apparatus intended for intermittent operation and yactuable -toproduce aninsecticidal gas comprising, iii-combination, a tank adapted to contain insecticidal liquid, means to deliver air under .pressure to-said tank, a metering valve to which saidliquid is rdelivered,.means includinga .iiovv regulator valve to conduct a supply -of air `under pressure 'to .said metering valve, a conduit bypassing said :now .regulator valve to deliver air under pressure -to .said vmetering valve, and a chamber through which passes. commingled air and liquid leaving .the meter valve.

y8. An .apparatus intended for intermittent operationand actuable to. .produce an insecticidal gas comprising, in combination, a tank adapted to contain insecticidal liquid, means to deliver .air under `pressure to said tank, a metering valve to. which said liquid isdelivered, means including a 'iiow regulator. valve to conduct a supply of air under pressure to said metering valve, a conduit bypassing said '110W regulator valve to deliver air under'pressure to said metering valve, a chamber through which passes commingled air and liquid leaving the metering valve and a heating element `in said chamber.

9. An apparatus intended for intermittent operation and actuable to produce an insecticidal gas comprising, in combination, a tank adapted to contain an insecticidal liquid, means to deliver air under pressure to said tank during operation of said apparatus so as to discharge the liquid therefrom, a source of liquid supply including a pipe line connected to said tank and adapted to permit liquid to new into said tank until a predetermined Vlevel is reached therein when the apparatus is shut-down following a period of operation, ymeans in said pipe line to prevent the flow of liquid into said tank during operation of the apparatus, and means connected to said line effective to convert 1liquid flowing therethrough -to a gaseous state prior to its discharge from the apparatus.

l0. An apparatus intended for intermittent operation and actuable to produce an insecticidal gas comprising, in combination, a tank adapted to contain an insecticidal liquid, means to deliver Aair. under pressure to said tank during operation of said apparatus so as to discharge the liquid therefrom, meansA in said apparatus to gasify said liquid during operation of said apparatus, a

i source of liquid supply including a pipe line connected to said tank and adapted to permit liquid to flow into said tank until a predetermined level .is reached therein "when the. apparatus is shut :down follovringaxiperiod. of operation, means in said pipe line to prevent the ow of liquid into said tank during operation of the apparatus, a bleeder line to return condensate from the gasifying means to said tank when 'the apparatus is shut down, and a restrictor in the liquid supply line to retard the flow of liquid into said tank so that said condensate may return thereto.

1l. An apparatus for gasifying a liquid comprising, in combination, a liquid supply source, a sealed tank for liquid having an inlet, a pipe line connecting said source with said inlet whereby liquid may flow by gravity into said tank, a check-valve in said line to prevent reverse flow of liquid from said tank to said source, means effective to convert said liquid to a gaseous state including a conduit connected into the supply line between the tank and the check-Valvafan air pressure tank, means to deliver air under pressure to said air pressure tank, a conduit connecting said air pressure tank with the liquid tank to force liquid therefrom and with the gasifying means, and a dehydrator in said conduit.

12. An apparatus for gasifying a liquid comprising, in combination, a liquid supply source, `a sealed tank for liquid having an inlet, a pipe line connecting said source with said inlet whereby liquid may now by gravity into said tank, a restrictor in said pipe line to regulate the ow of liquid into said tank, a check-valve in said line to prevent reverse ow of liquid from said tank to said source, eiective to convert said liquid to a gaseous state including a conduit connected into the supply line between the tank and the checkvalve, an air pressure tank, means to deliver air under pressure to said air pressure tank, a conduit connecting said air pressure tank with the liquid tank to force liquid therefrom and With the gasifying means, a dehydrator in said conduit, and means to return condensate from the gasifying means to the liquid tank when the apparatus is shut down, said restrictor preventing the excessive flow of liquid'to the tank during condensate return.

` ARTHUR G. HOWARD.

REFERENCES CITED UNITED STATES PATENTS Name Date Brouse Aug. 5, 1930 Number Certificate of Correction Patent No. 2,537,761 January 9, 1951 ARTHUR G. HOWARD It is hereby certified that error appears in lthe printed specification of the above numbered patent requiring correction as follows:

Column 4, line 47, after the Word of insert az'r; column 6, lines 57 and 58, Jfor delvered read delivered and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent OHice. Signed and sealed this 27th day of February, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

